Bernhard Hollunder

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We consider the problem of integrating Reiter's default logic into terminological representation systems. It turns out that such an integration is less straightforward than we expected, considering the fact that the terminological language is a decidable sublanguage of first-order logic. Semantically, one has the unpleasant effect that the consequences of a(More)
In a recent paper we have proposed terminological default logic as a formalism that combines means both for structured representation of classes and objects and for default inheritance of properties. The major drawback that terminological default logic inherits from general default logic is that it does not take precedence of more specific defaults over(More)
We consider diierent methods of optimizing the classiication process of terminological representation systems, and evaluate their eeect on three diierent types of test data. Though these techniques can probably be found in many existing systems, until now there has been no coherent description of these techniques and their impact on the performance of a(More)
The knowledge representation system KL-ONE first appeared in 1977. Subsequently many systems based on the idea of KL-ONE have been built. The formal model-theoretic semantics which has been introduced for KL-ONE languages [9] provides means for investigating soundness and completeness of inference algorithms. It turned out that almost all implemented KL-ONE(More)
We investigate subsumption algorithms for logic-based knowledge representation languages of the kl-one family. We deene an attribu-tive concept description language that contains the logical connectives conjunction, disjunction, and negation, as well as role quantiication, number restrictions and role intersection. We describe a rule based calculus to(More)
Possibilistic logic, an extension of first-order logic, deals with uncertainty that can be es­ timated in terms of possibility and necessity measures. Syntactically, this means that a first-order formula is equipped with a possi­ bility degree or a necessity degree that ex­ presses to what extent the formula is pos­ sibly or necessarily true. Possibilistic(More)